2 * Copyright (C) 2009-2010 PetaLogix
3 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
5 * Provide default implementations of the DMA mapping callbacks for
6 * directly mapped busses.
9 #include <linux/device.h>
10 #include <linux/dma-mapping.h>
11 #include <linux/gfp.h>
12 #include <linux/dma-debug.h>
13 #include <linux/export.h>
14 #include <linux/bug.h>
16 #define NOT_COHERENT_CACHE
18 static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
19 dma_addr_t *dma_handle, gfp_t flag,
22 #ifdef NOT_COHERENT_CACHE
23 return consistent_alloc(flag, size, dma_handle);
27 int node = dev_to_node(dev);
29 /* ignore region specifiers */
30 flag &= ~(__GFP_HIGHMEM);
32 page = alloc_pages_node(node, flag, get_order(size));
35 ret = page_address(page);
37 *dma_handle = virt_to_phys(ret);
43 static void dma_direct_free_coherent(struct device *dev, size_t size,
44 void *vaddr, dma_addr_t dma_handle,
47 #ifdef NOT_COHERENT_CACHE
48 consistent_free(size, vaddr);
50 free_pages((unsigned long)vaddr, get_order(size));
54 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
55 int nents, enum dma_data_direction direction,
58 struct scatterlist *sg;
61 /* FIXME this part of code is untested */
62 for_each_sg(sgl, sg, nents, i) {
63 sg->dma_address = sg_phys(sg);
65 if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
68 __dma_sync(sg_phys(sg), sg->length, direction);
74 static int dma_direct_dma_supported(struct device *dev, u64 mask)
79 static inline dma_addr_t dma_direct_map_page(struct device *dev,
83 enum dma_data_direction direction,
86 if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
87 __dma_sync(page_to_phys(page) + offset, size, direction);
88 return page_to_phys(page) + offset;
91 static inline void dma_direct_unmap_page(struct device *dev,
92 dma_addr_t dma_address,
94 enum dma_data_direction direction,
97 /* There is not necessary to do cache cleanup
99 * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
100 * dma_address is physical address
102 if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
103 __dma_sync(dma_address, size, direction);
107 dma_direct_sync_single_for_cpu(struct device *dev,
108 dma_addr_t dma_handle, size_t size,
109 enum dma_data_direction direction)
112 * It's pointless to flush the cache as the memory segment
113 * is given to the CPU
116 if (direction == DMA_FROM_DEVICE)
117 __dma_sync(dma_handle, size, direction);
121 dma_direct_sync_single_for_device(struct device *dev,
122 dma_addr_t dma_handle, size_t size,
123 enum dma_data_direction direction)
126 * It's pointless to invalidate the cache if the device isn't
127 * supposed to write to the relevant region
130 if (direction == DMA_TO_DEVICE)
131 __dma_sync(dma_handle, size, direction);
135 dma_direct_sync_sg_for_cpu(struct device *dev,
136 struct scatterlist *sgl, int nents,
137 enum dma_data_direction direction)
139 struct scatterlist *sg;
142 /* FIXME this part of code is untested */
143 if (direction == DMA_FROM_DEVICE)
144 for_each_sg(sgl, sg, nents, i)
145 __dma_sync(sg->dma_address, sg->length, direction);
149 dma_direct_sync_sg_for_device(struct device *dev,
150 struct scatterlist *sgl, int nents,
151 enum dma_data_direction direction)
153 struct scatterlist *sg;
156 /* FIXME this part of code is untested */
157 if (direction == DMA_TO_DEVICE)
158 for_each_sg(sgl, sg, nents, i)
159 __dma_sync(sg->dma_address, sg->length, direction);
163 int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
164 void *cpu_addr, dma_addr_t handle, size_t size,
168 unsigned long user_count = vma_pages(vma);
169 unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
170 unsigned long off = vma->vm_pgoff;
173 if (off >= count || user_count > (count - off))
176 #ifdef NOT_COHERENT_CACHE
177 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
178 pfn = consistent_virt_to_pfn(cpu_addr);
180 pfn = virt_to_pfn(cpu_addr);
182 return remap_pfn_range(vma, vma->vm_start, pfn + off,
183 vma->vm_end - vma->vm_start, vma->vm_page_prot);
189 const struct dma_map_ops dma_direct_ops = {
190 .alloc = dma_direct_alloc_coherent,
191 .free = dma_direct_free_coherent,
192 .mmap = dma_direct_mmap_coherent,
193 .map_sg = dma_direct_map_sg,
194 .dma_supported = dma_direct_dma_supported,
195 .map_page = dma_direct_map_page,
196 .unmap_page = dma_direct_unmap_page,
197 .sync_single_for_cpu = dma_direct_sync_single_for_cpu,
198 .sync_single_for_device = dma_direct_sync_single_for_device,
199 .sync_sg_for_cpu = dma_direct_sync_sg_for_cpu,
200 .sync_sg_for_device = dma_direct_sync_sg_for_device,
202 EXPORT_SYMBOL(dma_direct_ops);
204 /* Number of entries preallocated for DMA-API debugging */
205 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
207 static int __init dma_init(void)
209 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
213 fs_initcall(dma_init);